U.S. patent number 6,186,078 [Application Number 09/430,486] was granted by the patent office on 2001-02-13 for low profile material handling platform.
This patent grant is currently assigned to Alltrista Corporation. Invention is credited to Henry F. Brown.
United States Patent |
6,186,078 |
Brown |
February 13, 2001 |
Low profile material handling platform
Abstract
A deck is defined by closely spaced molded ribs with pairs of
ramped tine entry openings molded adjacent each edge which are
tapered to provide maximum clearance. A narrow lip extends at an
angle upwardly from each edge, permitting the platform to be
engaged and manipulated by conventional slip sheet handling
equipment, while the tine entry ramps permit a powered forklift
truck to engage its fork tines beneath the platform. To facilitate
deflection of the platform ribs on entry of the forklift tines, the
ribs in the path of the tines may have curved valleys, while ribs
not in the path may have generally square valleys. The platform may
also be constructed through twin sheet thermoforming, foam molding,
corrugated paperboard assembly. The platform has a horizontal load
support deck with side walls which extend downwardly. Two tine
inlet access openings are defined in each side wall, with the
height of each access opening being less than the maximum height of
a forklift tine. Downwardly opening channels extend between each
pair of tine access openings on the opposite side walls and are
separated by downwardly extending support pads. A lip extends
upwardly and outwardly from the support pads on each side of the
platform, and each lip has a clearance opening in front of an
access opening to permit the forklift times to pass through the lip
and into engagement with the channels. The platform may also be
inverted to serve as a load cap.
Inventors: |
Brown; Henry F. (Portage,
WI) |
Assignee: |
Alltrista Corporation
(Indianapolis, IN)
|
Family
ID: |
23707759 |
Appl.
No.: |
09/430,486 |
Filed: |
October 29, 1999 |
Current U.S.
Class: |
108/57.25;
108/55.1; 248/346.02 |
Current CPC
Class: |
B65D
19/0036 (20130101); B65D 19/0014 (20130101); B65D
19/0002 (20130101); B65D 2519/00034 (20130101); B65D
2519/00557 (20130101); B65D 2519/00069 (20130101); B65D
2519/00402 (20130101); B65D 2519/00796 (20130101); B65D
2519/00288 (20130101); B65D 2519/00333 (20130101); B65D
2519/00318 (20130101); B65D 2519/00348 (20130101); B65D
2519/00338 (20130101); B65D 2519/00268 (20130101); B65D
2519/00562 (20130101); B65D 2519/00293 (20130101) |
Current International
Class: |
B65D
19/00 (20060101); B65D 019/22 () |
Field of
Search: |
;108/51.4,55.3,55.1,55.5,57.25 ;248/346.02 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; Peter R.
Assistant Examiner: Fisher; Michael J.
Attorney, Agent or Firm: Lathrop & Clark LLP
Claims
I claim:
1. A material handling support platform comprising a unitary
plastic sheet having a plurality of upwardly extending closely
spaced ribs, wherein each rib has an upper surface, and the ribs
are spaced from one another by valleys having lower portions
defining a downwardly facing lower surface, wherein the rib upper
surfaces define a generally horizontal support deck for the receipt
thereon of a load, and wherein the platform has a perimeter defined
between parallel front and rear edges, and two parallel side edges,
and wherein a lip extends upwardly and outwardly from each of the
front edge, the rear edge, and the two side edges, and wherein two
tine entry openings are defined adjacent at least one of the four
edges, each tine entry opening comprising a plurality of tapered
ribs extending generally perpendicular to said edge, the plurality
of tapered ribs defining an inverted ramp which extends away from
the support deck as the ramp extends inwardly from said edge, said
two tine entry openings being positioned to receive the spaced
parallel tines of a fork lift truck.
2. The material handling support platform of claim 1 wherein two
tine openings are defined adjacent each of the four edges of the
platform, and wherein portions of the downwardly facing lower
surface which extend between opposed tine openings on opposite
edges define a tine engagement first region, and the remaining
portions of the downwardly facing lower surface defining a second
region, and wherein the cross-sections of the valleys defining the
first region are generally curved.
3. The material handling support platform of claim 2 wherein the
cross-sections of the valleys defining the second region are
generally square.
4. The material handling support platform of claim 1 wherein the
distance between the downwardly facing lower surface and the
support deck is between one quarter inch and one inch.
5. The material handling support platform of claim 1 further
comprising a flat rib which runs parallel to one of said edges of
the platform, extending approximately in the plane of the
horizontal support deck, the flat rib receiving thereunder a strap
for retaining of a load on the deck.
6. The material handling support platform of claim 1 further
comprising a peripheral groove recessed within the horizontal
support deck for receipt therein of a pallet sleeve.
7. A material handling support platform comprising:
a load support deck having a top surface which extends horizontally
and faces upwardly, wherein the deck has a front edge, a rear edge
spaced rearwardly from the front edge, and two spaced side edges
extending between the front edge and the rear edge;
a front wall extending downwardly from the front edge;
a rear wall extending downwardly from the rear edge;
side walls extending downwardly from each of the two side
edges;
portions of the support deck which are spaced below the top surface
and which define lower engagement regions;
at least two tine access openings defined in the front wall, a tine
access opening being defined between two ground engagement
regions;
at least two tine access openings defined in the rear wall opposite
the front wall tine access openings;
at least two downwardly opening channels defined by portions of the
support deck, wherein a first channel extends between one of the
two tine access openings on the front wall and the opposite tine
access opening on the rear wall, and a second channel extends
between the other of the two tine access openings and the opposite
tine access opening on the rear wall, wherein each channel has a
tine engagement surface which faces downwardly and which is spaced
above the deck lower engagement regions and below the deck top
surface; and
a lip which extends upwardly and outwardly from the deck adjacent
the front wall, the lip extending at a level below the tine
engagement surfaces of the channels, wherein portions of the lip
define a clearance opening adjacent each tine access opening in the
front wall, to thereby permit two forklift tines to pass through
the lip, into the front wall tine access openings and into
engagement with the tine engagement surfaces of the first channel
and the second channel.
8. The platform of claim 7 further comprising a flat rib which runs
parallel to one of said edges of the platform, extending
approximately in the plane of the horizontal support deck, the flat
rib receiving thereunder a strap for retaining of a load on the
deck.
9. The platform of claim 7 further comprising a peripheral groove
recessed within the horizontal support deck for receipt therein of
a pallet sleeve.
10. The platform of claim 7 wherein the deck is comprised of a two
sheets of thermoplastic material fused together in the twin sheet
thermoforming process, a plurality of ribs being defined between
the two sheets, wherein the spacing between said ribs is less above
the tine engagement surfaces, than above the lower engagement
regions.
11. The platform of claim 7, wherein the platform is fabricated of
a plurality of corrugated paperboard elements.
12. The platform of claim 7 wherein the platform is fabricated of
molded plastic foam.
13. A material handling support platform comprising:
a load support deck having a top surface which extends horizontally
and faces upwardly, wherein the deck has a front edge, a rear edge
spaced rearwardly from the front edge, and two spaced side edges
extending between the front edge and the rear edge;
a front wall extending downwardly from the front edge;
a rear wall extending downwardly from the rear edge;
side walls extending downwardly from each of the two side
edges;
portions of the support deck which are spaced below the top surface
and which define lower engagement regions;
at least two tine access openings defined in the front wall, a tine
access opening being defined between two ground engagement
regions;
at least two tine access openings defined in the rear wall opposite
the front wall tine access openings; and
at least two downwardly opening channels defined by portions of the
support deck, wherein a first channel extends between one of the
two tine access openings on the front wall and the opposite tine
access opening on the rear wall, and a second channel extends
between the other of the two tine access openings and the opposite
tine access opening on the rear wall, wherein each channel has a
tine engagement surface which faces downwardly and which is spaced
above the deck lower engagement regions and below the deck top
surface, wherein the distance between the lower engagement regions
and the tine engagement surfaces is less than two inches, and less
than the height of a forklift tine which is to be interposed into
the channels, such that the platform deck lower engagement regions
are spaced above a support surface when forklift tines are engaged
with the deck lower engagement regions and the support surface.
14. The platform of claim 11, wherein the ratio of the area of the
deck lower engagement regions to the total area of the deck having
a length l and a width w, where the width of each channel is n, is
defined by the relation. ##EQU3##
Description
CROSS REFERENCES TO RELATED APPLICATIONS
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED
RESEARCH AND DEVELOPMENT
BACKGROUND OF THE INVENTION
The Present invention relates to material handling platform in
general, and more particularly to reduced height load supports.
Shipping and Storage are significant cost components of any product
which must make its way from a manufacturer to an end user. The
bundling of multiple items into uniform loads with associated
structure for engagement by material handling equipment such as
forklift trucks has permitted a degree of automation and
repeatability in the transportation of goods.
For many years uniform or "palletized" loads were built upon wooden
pallets. The wooden pallet is very stiff, is manufactured from
commonly available low cost material, and provides a large vertical
clearance to receive the metal tines of a forklift truck or the
wheeled tines of a hand truck. More recently, plastic pallets have
been substituted for wooden ones in view of their greater
consistency, usable life, and nestability.
For some loads, however, the high profile of the wooden or plastic
pallet, approximately 4-5 inches, represents an unacceptable
increase in the shipping volume of the product. This is a
particular concern in automated loading applications, such as on
railway freight cars, where excessive vertical height of the
palletized load of even a few inches might limit the number of
stackable units to two levels, rather than three. To minimize
support height, loads may be placed on narrow slip sheets, which
provide no clearance for fork tines. The conventional slip sheet
may be formed of corrugated paperboard, or an extruded or molded
plastic sheet, which may have a corrugated paperboard sheet
adhesively attached thereto. The slip sheet is typically wider than
the load supported thereon, extending outwardly in an upwardly
extending lip. In addition to being of lower volume, slip sheets
are usually of lower cost than a full height pallet.
Where slip sheet mounted loads are widely used, material handling
facilities are outfitted with specialized forklift trucks which
have mechanisms for clamping on to the slip sheet lip and dragging
the load onto the forklift tines. The slip sheet supported load is
usually discharged from the truck by a vertical panel actuated by a
scissors joint linkage which pushes the load off the tines.
The conventional slip sheet has several limitations. First, because
of its very low-profile, generally from 1/8 in. to 1/4 in., its
rigidity is low, and its resistance to warping, twisting, bending,
and folding is correspondingly low. This susceptibility to damage
in shipping makes re-use problematic. Second, the narrow sheet
provides minimal isolation of the supported load from support
surface irregularities such as gouges, cracks, loose hardware,
splinters and the like commonly found in semi truck trailers, rail
cars, and factory floors. The nonrigid slip sheet also provides
minimal load distribution of the lifting fork tines. The load is
thus open to damage from the concentrated impact of the material
handling equipment. Third, facilities which handle primarily loads
on high-profile pallets or skids may not be equipped with
specialized slip sheet handling equipment. In some situations a
slip sheet supported load may be engaged by conventional powered
forklift trucks by ramming the tapered tines beneath the slip sheet
lip. This approach offers significant opportunity for product
damage.
What is needed is a low-profile load support which provides some
protection for the load from support surface irregularities and
load handling impact, and which is readily engaged by conventional
fork lift equipment.
SUMMARY OF THE INVENTION
The material handling support platform of this invention has
structure permitting it to be manipulated by fork lift trucks which
are outfitted with conventional slip sheet engaging accessories, or
by fork lift trucks with bare tines without such accessories. The
platform is of much lower profile than a conventional wooden pallet
or a conventional nine leg plastic pallet. The platform may be
manufactured as a single sheet thermoformed thermoplastic part
having a deck defined by closely spaced molded ribs. Pairs of
ramped tine entry openings are molded adjacent each edge of the
platform. The tine entry ramps are tapered to provide maximum
clearance at the edge. However, the maximum height of the opening
is less than the maximum thickness of a forklift tine. A narrow lip
extends at an angle upwardly from each edge, permitting the
platform to be engaged and manipulated by conventional slip sheet
handling equipment. The tine entry ramps, however, permit a powered
forklift truck to engage its fork tines beneath the platform. To
facilitate deflection of the platform ribs on entry of the forklift
tines, the ribs in the path of the tines may have curved valleys,
while ribs not in the path may have generally square valleys.
The platform may also be constructed through alternative
manufacturing processes, such as twin sheet thermoforming, foam
molding, corrugated paperboard assembly, or others. In general, the
platform has a horizontal load support deck with side walls which
extend downwardly. Two tine inlet access openings are defined in
each side wall, with the height of each access opening being less
than the maximum height of a forklift tine. Downwardly opening
channels extend between each pair of tine access openings on the
opposite side walls and are separated by downwardly extending
support pads. A lip extends upwardly and outwardly from the support
pads on each side of the platform, and each lip has a clearance
opening in front of an access opening to permit the forklift times
to pass through the lip and into engagement with the channels. The
platform may also be inverted to serve as a load cap. As a load
cap, the platform pads may be provided with projections which
engage with recesses on an overlying platform. In such an
application the height of the tine access openings would be
selected such that a forklift tine could be fully received between
the two overlying access openings and channels to permit an
overlying loaded platform to be removed by a forklift vehicle
without disturbing the underlying load.
It is an object of the present invention to provide a material
handling support platform which can be readily engaged by a
forklift truck with or without slip sheet handling attachments.
It is also an object of the present invention to provide a low
profile material handling support platform which is reusable and
recyclable.
It is another object of the present invention to provide a low-cost
material handling support platform.
It is a further object of the present invention to provide a
low-profile material handling support platform which is adapted to
manipulation by automated equipment.
It is an additional object of the present invention to provide a
material handling support platform which can be manipulated by slip
sheet handling equipment, yet which minimizes disturbance of the
supported goods.
It is yet another object of the present invention to provide a
material handling support platform which isolates the supported
load from irregularities in the shipping or storage support
surface.
Further objects, features and advantages of the invention will be
apparent from the following detailed description when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top isometric view of the load support platform of this
invention being carried on a powered forklift truck, with a load
shown in phantom view.
FIG. 2 is a bottom plan view of the load support platform of FIG.
1.
FIG. 3 is a fragmentary bottom isometric view of the load support
platform of FIG.1.
FIG. 4 is a fragmentary cross-sectional view of the load support
platform of FIG. 2 taken along section line 2--2.
FIG. 5 is a fragmentary cross-sectional view of a modified load
support platform, similar to the one of FIG. 1 being engaged by the
tines of a forklift truck.
FIG. 6 is a top isometric view of an alternative embodiment twin
sheet thermoformed load support platform of this invention.
FIG. 7 is a cross-sectional view of the load support platform of
FIG. 6 taken along section line 7--7.
FIG. 8 is a cross-sectional view of the load support of FIG. 6 take
along section line 8--8.
FIG. 9 is a fragmentary cross-sectional view of the load support
platform platform of FIG. 6 engaged and elevated on the tines of a
fork lift truck.
FIG. 10 is a fragmentary enlarged isometric view, partially broken
away in section, of the lip of a load support platform similar to
the one of FIG. 6, but provided with a groove for engaging a pallet
sleeve, and showing portions in an as-molded condition prior to
routing and trimming.
FIG. 11 is a top isometric view of an alternative embodiment load
support platform this invention constructed of corrugated
paperboard.
FIG. 12 is a cross-sectional view of the platform of FIG. 11 taken
along section line 12--12.
FIG. 13 is an exploded isometric view of two stacked loads
employing alternative embodiment load support platforms of this
invention constructed of plastic foam.
FIG. 14 is a fragmentary cross-sectional view of the stacked loads
of FIG. 13, showing the insertion of forklift tines between the two
stacked loads.
FIG. 15 is an isometric view of a twin sheet thermoformed material
handling load support platform of this invention which does not
have slip sheet lips.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring more particularly to FIGS. 1-15, wherein like numbers
refer to similar parts, a material handling load support platform
20 is shown in FIGS. 1-5. The platform 20 is formed from a unitary
sheet of plastic. The platform 20 may be formed from a single sheet
of thermoplastic material such as polyethylene in the vacuum
thermoforming process. In the single sheet thermoforming process,
an extruded thin sheet of plastic is heated and brought into
contact with a mold which has been provided with multiple air
passages. The heated sheet engages the mold while air is drawn
through the passages to cause the plastic to conform to the shape
of the mold. The molded sheet is cooled, removed from the mold, and
trimmed and routed as necessary. Alternatively, the platform 20
could be made as an injection molded part.
The platform 20 has an array of ribs 22 spaced by valleys 24. The
top surfaces 26 of the ribs 22 extend in a common horizontal plane
to define a support deck 28 which receives a load 30 of goods. The
load 30 will typically have the capacity to retain its own
integrity, either by being encased in a single carton, or, if
multiple smaller containers form the load, by being shrink-wrapped
in plastic, or otherwise strapped together. The deck 28 is
terminated by a rectangular perimeter 32 defined by a front edge 34
which is parallel to a rear edge 36, and two parallel side edges
38. The support deck 28 will typically have dimensions of a
standard slip sheet or pallet, for example 40 inches by 48
inches.
To permit the platform 20 to be manipulated by conventional slip
sheet handling equipment, plastic tabs or lips 40 extend upwardly
and outwardly from each edge 34, 36, 38. Each lip 40 is about 3
inches wide and extends the length of the edge. The lips extend
upwardly from the support deck 28 at an angle of 10-30 degrees and
are thereby readily graspable by mechanical equipment. To provide
for convenient manual handling of the unloaded platforms 20, each
lip 40 may be provided with one or more hand holes 44.
The platform 20 may be manufactured in various thicknesses
depending upon the requirements of a particular application. The
illustrated platform 20, as shown in FIG. 5, has a height from the
top surfaces 26 of the ribs 22 to the lower surfaces 42 of the
valleys 24 of approximately 3/8 inches. Such a platform is expected
to be adequate for supporting loads of about 2,500 pounds on a
single pallet, and, when at the base of a four platform-load stack,
10,000 pounds.
To permit the platform 20 to be manipulated by a forklift truck 45
which is not outfitted with slip sheet handling equipment, certain
ribs are configured to assist entry of bare forklift tines 48
beneath the lower surface 46 of the platform 20 defined by the
lower surfaces 42 of the valleys 24. First, to assist initial
engagement between the forklift tines 48 and the platform 20, pairs
of tine entry openings 50 are formed on each edge 34, 36, 38. As
shown in FIG. 3, each tine entry opening 50 is comprised of a
plurality of tapered ribs 52 extending generally perpendicular to
the edge. The group of tapered ribs 52 defines an inverted ramp 54
which extends downwardly away from the support deck 28 as the ramp
extends inwardly from the edge. The tapered ribs 52 terminate at
and are joined by a perpendicular terminal rib 56. The terminal rib
56 may have a lower surface 58 which is in the same plane as the
lower surfaces 42 of the valleys 24, or, preferably as shown in
FIG. 3, the terminal rib lower surface will be slightly recessed
from the lower surfaces of the platform valleys generally. Each
ramp rib 52 extends approximately 11/2 inches from the perimeter
edge to the terminal rib. Each inverted ramp 54 extends
approximately 7.5 inches along the edge to accommodate the
approximately four inch to six inch width of a conventional
forklift tine 48. A forklift tine 48 may be 48 inches or longer and
have a maximum thickness of 11/4 in. to 2 inches. However, the
entry end or tip 64 of the forklift tine 48 may be only 3/16 inches
thick, with the tine increasing in thickness over a tapered length
of about 18-20 inches. Thus, although the tine entry opening 50 in
the illustrated embodiment is less than 3/8 inches high, the tip 64
of the time readily enters therein.
To facilitate the elevation of the platform onto the tines 48,
which will typically be taller than the inlet entry to the support
platform 20 itself, the ribs are formed to readily deflect as the
tines enter. As shown in FIG. 5, the valleys 60 between ribs 22
which are in the path of a tine 48 have a generally rounded
cross-section. The valleys 62 between ribs 22 which are not in the
path of a tine, on the other hand, as shown in FIG. 4, have a
generally square cross-section. Although many rib patterns are
possible, the rib pattern shown in FIG. 2 is designed to cushion
the load when supported on irregular support surfaces, to absorb
shock vibration during transport, and to avoid ribs which run
parallel to the forklift tines where possible. The performance of
the platform as far as absorbing shock may be adjusted by modifying
the attributes of the ribs, including the draft angle of the rib,
the thickness of the walls of the rib, the shape of the
rib--whether more rounded or more square--, and the number and
spacing of the ribs. Depending on the size of the load to be
supported, and the level of dynamic shock absorption these features
may be varied.
As indicated, the valleys between ribs may be categorized as those
which may be contacted by a tine, and those which should not be
contacted by a tine. The underside of the platform 20 may thus be
divided into two regions, a tine engagement region 66 which
encompasses all the rounded valleys 60, and a second region 68
which will typically not contact a time and which encompasses all
the square valleys 62. The tine engagement region 66 extends in
overlapping rectangular bands between the tine entry openings 50.
The second region 68 comprises the comers, the perimeters areas
between the two tiny entry openings 50 along one edge, and a
rectangular region in the center.
The platform 20 is configured to allow it to be approached from any
of its four edges. Hence, portions of the tine engagement region 66
may be expected to engage a tine extending in two perpendicular
directions. Thus the tine engagement region 66 has a plurality of
diagonal ribs extending from a comer of the platform to the center,
with the results that many of the curved valleys will engage the
forklift tines 48 obliquely. The rib pattern minimizes any fold
lines or weak lines, for increased rigidity.
The platform 20 has several advantages. First, the ribbed
configuration absorbs some of the shock and vibration of
transportation. Second, the platform provides greater distance
between the load and any loadbearing surfaces that have
irregularities. There are many occasions in which a palletized load
can encounter surface irregularities which are potentially damaging
to the load. For example, oftentimes the platform may be slid onto
a wooden pallet, and then the unit load is transported with
conventional pallet handling equipment. The platform 20 provides
some protection for its contents from normal wood skids, nail
heads, and slivered and broken boards, which could easily deform or
ruin the contents. Truck trailer bottoms and rail car bottoms also
may have irregular conditions. Over many uses and loading cycles,
trucks and rail car bottoms may be gouged or otherwise damaged by
the downward angling of lift truck tines.
The platform 20 may be handled both as a slip sheet with
conventional slip sheet handling equipment, and by a forklift truck
without such equipment. However, the platform 20 offers greater
separation from the load to the load bearing surfaces than a
conventional uniform thickness plastic slip sheet. As shown in FIG.
5, as the forklift tines 48 engage the valleys 60, the plastic of
the platform 20 deflects, raising the load, and creating clearance
for entry of the tines. When the tines are fully engaged with the
lower surface of the platform 20, as shown in FIG. 1, the portions
contacting the tines are elevated above the floor or other support
surface. Because of the shallow depth of the platform 20, a certain
amount of deflection will occur between the two tines. The platform
will not remain perfectly flat. The load may cause the platform to
contact the floor 70 between the tines and offer some resistance.
This frictional resistance between the under surface of the
platform 20 and the floor is very helpful when it is desired to
unload the platform from the forklift tines 48. Because the
platform bows between the tines 48, the lower surface 46 between
the tines engages the floor 70 before the tines themselves touch
the floor. Therefore, the frictional engagement of the platform 20
with the floor 70 over a wide area can be greater than the
frictional engagement forces between the platform and the tines 48,
permitting the tines to be extracted from the platform, and the
platform to be disengaged from the forklift truck. This
disengagement is most expeditiously obtained by tilting the
forklift tines downwardly and backing up the truck, thereby
gradually retracting the tines from engagement beneath the platform
20. This technique may also be used to set a platform-mounted load
on another load.
It should be noted that the platform top surface may be formed with
shallow protrusions, for example approximately 1/32 inch tall,
projecting upwardly from the rib top surfaces 26, which serve to
mechanically engage the load disposed on the platform. The
protrusions may have a surface appearance similar to grip plate,
such as the pattern of ribs shown in FIG. 15, of U.S. Pat. No.
5,566,624, the disclosure of which is incorporated by reference
herein.
It should be noted that the platform made from conventional plastic
materials, such as polyethylene, could also be provided with a slip
resistant surface for particular applications. The slip resistant
surface may be provided on the top or the bottom or on both
surfaces. The slip resistant surface may be co-extruded with the
initial plastic sheet, or it may be sprayed on after molding.
Examples of non-slip coatings are found in U.S. Pat. Nos. 4,693,507
and 4,428,306, the disclosures of which are incorporated by
reference herein.
In certain applications, for example the shipment of containers of
granular or liquid material, the platform 20 has the advantageous
attribute of restricting flow of material beyond the confines of
the platform. As best shown in FIG. 1 and FIG. 4, the platform 20
support deck 28 is unperforated, and the edges are all elevated
above the level of the floor 70. Hence, should a supported beverage
can burst or be crushed, the liquid--at least in limited
quantities--can be contained within the valleys of the support
deck. This spillage containment serves to prevent structural damage
to one load being the cause of liquid damage to a load below.
Although the valleys of the support deck have been shown as
discrete and non-connected, a labyrinthine pattern of connected
ribs could also be employed, thereby facilitating the equal
distribution of a spilled liquid throughout the platform
surface.
The platform 20 in FIG. 5 has been shown modified from the platform
of FIGS. 1-4 in one respect, in that a flat wide rib 69 is provided
running parallel to an edge of the platform. The wide rib 69
extends in the plane of the top deck 28, elevated above the valleys
24. Thus a strap 71 which is wrapped around the load 30 supported
on the platform 20 extends beneath the wide rib 69, thereby
securing the load to the platform, while at the same time retaining
the strap 71 out of potential engagement with the incoming forklift
tine 48. Similar flat wide ribs may be provided parallel to each
edge of the platform.
An alternative embodiment platform 72 of this invention is shown in
FIGS. 6-10. The platform 72 is formed of thermoplastic sheets in
the twin sheet thereof forming process. In the twin sheet
thermoforming process a first extruded thermoplastic sheet is
heated and molded in a lower vacuum forming mold, while a second
extruded thermoplastic sheet is heated and molded in an upper
vacuum forming mold. The two molded sheets, while still hot, are
brought together and fused at selected locations to form a single
part. The part is cooled and ejected from the molds where it is cut
and trimmed. The twin sheet thermoforming process is particularly
effective in producing stiff parts with minimal plastic
material.
As shown in FIG. 6, the platform 72 may be formed with a load
support deck 74 which has a substantially featureless upwardly
facing top surface 76. The platform 72 may be of the same height as
the platform 20, however for added load isolation it may be
thicker, for example about 11/2 inches from the top surface 76 to
lower engagement regions 78 on the underside of the deck 74 spaced
beneath and parallel to the top surface. As is common in twin sheet
thermoformed structures, the lower sheet may be formed into an
array of ribs which are fused to the flat upper sheet. The rib
structure may be a pattern of angled ribs similar to the array
shown in FIG. 2. Although, it should be noted that the width and
spacing of ribs will vary with the depth of the deck 74, i.e.:
deeper decks will have ribs which are wider and lesser in number.
Other rib patterns, for example those involving longitudinally
aligned ribs which are fused to one another, such as those shown in
U.S. Pat. No. 5,566,624, the disclosure of which is incorporated by
reference herein
The deck has a front edge 82, a rear edge 84 spaced parallel to the
front edge, and two side edges 86 which extend between the front
edge and the rear edge. A front wall 88 extends from the front edge
82 between the top surface 76 and the lower engagement regions 78.
A rear wall 90 extends downwardly from the rear edge 84, and side
walls 92 extend downwardly from the side edges 86. Two tine inlet
openings 94 are formed in each of the front wall 88, rear wall 90,
and side walls 92. The tine inlet openings 94 on opposite side
walls are aligned with one another.
The platform 72 has downwardly opening channels 80 formed in the
underside of the deck 74. Each channel 80 extends between a tine
inlet opening 94 on one wall beneath the deck to the tine inlet
opening on the opposite wall. As shown in FIGS. 7 and 8, the
channels 80 extend all the way across the underside of the platform
72 and two sets of two channels intersect each other providing four
way entry to the underside of the deck 74 as shown in FIG. 9, the
recessed channels 80 are significantly shallower than the height of
a forklift tine 48. For example, the height of the deck 74 may be
1.5 inches, while the depth of the channels is about 0.5 inches.
The tine inlet openings 94 need not be provided with ramps, because
the tips 64 of the forklift tines 48 are themselves tapered, and
the height of the inlet openings allows the tines to make initial
entry into the channels 80. However, as an aid to the tines finding
the tine inlet, the deck 74 may be provided with inverted ramps at
each tine inlet opening 94. As the powered lift truck advances on
the platform 72 the tines 48 are driven into the channels and the
platform is elevated. The tines 48 make contact with tine
engagement surfaces 96 which define the uppermost downwardly facing
portions of the channels 80.
To allow the platform 72 to be manipulated by conventional slip
sheet handling equipment, a lip 98 extends upwardly and outwardly
from each of the front wall 88, the rear wall 90, and the side
walls 92. The lips 98 extend from the deck 74 at a position spaced
below the top surface 76, preferably at a level close to the ground
engagement regions 78. As in the platform 20, the lips 98 extend at
10-30 degrees and are 3-4 inches long. The lips 98 are provided
with hand holes 100 for manual maneuvering of the unloaded
platforms 72. To allow the forklift tines 48 to enter the tine
inlet openings 94, clearance openings 102 are defined in each lip
adjacent the tine inlet openings.
The clearance openings 102 allow the forklift tines 48 to pass
beneath the lip 98 and extend into the channels 80 for engagement
with the tine engagement surfaces 96 of the deck 74. To permit
this, the clearance openings 102 should extend vertically about as
high as the level of the tine engagement surfaces 96. Each lip 98
thus has a continuous strip 104 joined to the deck 74 by three
connecting segments 106. As shown in FIG. 10, for convenience of
thermoforming and manufacture, the tine inlet openings and lip
access openings 102 may be covered in the as-molded part by a cap
108. The surrounding wall and lip serve as router guides in the
trimming stage of manufacture to easily remove the cap 108 and
reveal both openings simultaneously.
The platform of FIG. 10 has been shown with an optional feature,
where it is desired to use the platform with a peripheral sleeve
109. The sleeve 109 is a four-walled vertically extending element
which may be used together with a cap to enclose loose goods. The
platform may be provided with a peripheral groove 111 which extends
around the top surface of the platform and which is recessed to
receive the lower edge of the sleeve 109.
The platform 72 may be engaged by the tines of a forklift truck and
transported from place to place. When it is desired to disengage
the fork tines from the pallet deck, the tines are tipped upwardly
slightly to bring those lower engagement regions 78 farthest from
the truck 45 into contact with the floor 70. Because the forklift
tines are tapered at the tips, this inclining of the platform
drives the tine tips into the channels 80, while the lower
engagement regions 78 experience frictional resistance by contact
with the floor 70. This frictional resistance serves to hold the
platform 72 in place on the floor 70 as the truck 45 continues to
withdraw until it is fully separated from the platform 72.
It should be noted that the platform deck 74 has the capability for
greater engagement with the floor 70 than a conventional pallet
with a deck which is supported above the floor on legs. The
channels need only be somewhat wider than the tines themselves, for
example about seven inches wide. The proportion of the area of the
deck which engages the floor 70 or underlying load may be
calculated as follows:
where l is the length of the deck, and w is the width of the deck,
and n is the width of a channel:
the proportion of floor engaging region area to total area may be
expressed as: ##EQU1##
Thus, in the extreme case of no channels (n=0), it will be seen
that the entire deck will engage the floor. In the illustrated
platform, in which the channels are about 7 inches wide, and the
pallet deck is 40 inches wide by 48 inches long, the proportion
which engages the floor is ##EQU2##
Thus it will be seen that the platform 72 provides nearly 50
percent engagement with the floor. A greater amount of engagement
is desirable as it spreads the load of the platform over a greater
area and thus has lower stress overall. This is particular
desirable when one platform is stacked upon an underlying load, and
it is desired to avoid damaging the underlying load.
A platform 110 of this invention fabricated of corrugated
paperboard sheets is shown in FIGS. 11-12. The platform 110 has a
deck 112 comprised of multiple layers of corrugated paperboard
adhesively joined together. The channels 114 on the underside of
the deck 112 are formed by adhesively connecting smaller corrugated
paperboard elements 118 together to define the channels 114
therebetween. The platform 110 has a lip 116, also formed of
corrugated paperboard and scored or otherwise folded to extend
upwardly and outwardly from the base of the deck 112. The lip 116
extends from tabs which are glued to the smaller corrugated
elements 118. The channels extend from tine inlet openings 120. The
lips 116 have die-cut tine clearance openings 122.
Another alternative embodiment platform 124 is shown in FIGS.
13-14. The platform 124 is similar in exterior volume to the
platform 72, but is formed as a molded foam part. The platform 124
has a deck 126 with recessed channels 128 which extend from tine
entry openings 130 and which are not as deep as the forklift tines.
A lip 132 extends upwardly and outwardly from the lower engagement
regions 134 of the deck. The platform 124 is preferably formed of a
resilient foam to provide additional insulation of the load from
support surface irregularities and disturbances associated with
movement of the platform. The foam could be polyurethane foam,
polystyrene, could be generically polymer, could be open or closed
cell.
The foam is reinforced at the lip, for example, by inserting a
flexible plastic part into the mold prior to foaming, or by placing
a thin continuous plastic sheet sheet in the mold, to which foam is
added.
The platform 124 may be inverted such that the engagement regions
134 face upwardly, and may thus be used as a load cap. The platform
124 may be strapped or shrink-wrapped to the underlying load.
Although not shown in FIG. 13, the engagement regions 134 may be
provided with interlocking recesses and projections, so that an
overlying platform 124 will mate with the cap and restrict sideward
displacement. The recesses 136, and protrusions 138 may take the
form of circular depressions or dimples, and circular projections.
As shown in FIG. 14, although there is not sufficient depth in one
channel to fully receive the forklift tines 48, when the platform
of an overlying load is engaged with the underlying, the combined
depth of the adjacent channels 128 is sufficient to permit a
forklift truck to engage the overlying load on the platform 124
without disturbing the underlying load. Although for clarity the
lips of the platform have been illustrated as extending outwardly
and downwardly on the cap, in practice the cap will typically be
shrink-wrapped or strapped onto the underlying load or to a sleeve
supported on the underlying platform.
In conventional 9-leg pallets, which have decks which are spaced
4-5 inches above the floor by legs, a significant level of stress
is found in the vertical supporting members, that is the walls of
the pallet legs, because there are not very many of them, and
because they have extend so high. The platforms disclosed above
have a tremendous advantage over leg-elevated pallets, in that the
deck itself rests directly on the ground, permitting a great number
of vertical members, i.e. the vertically extending walls of the
ribs, and allowing those vertical members to be comparatively very
short, i.e. from under an inch to about 2-3 inches. The greater
performance of plastic in this short vertical members, allows a
pallet of a given load support capacity to be manufactured at a
greatly reduced price when compared to a conventional 9-leg
pallet.
There is a major cost relationship between height and cost of a
material handling platform. Another alternative embodiment platform
of this invention is shown in FIG. 15. The platform 140 maybe
identical to the platform shown in FIG. 6, with the difference that
the lips may be eliminated. Such a platform 140 is adapted
exclusively for manipulation by fork lift trucks not having
slip-sheet handling accessories. The platform 140 has channels 142
which extend between tine inlet openings 144 on opposite edges of
the pallet. As opposed to a conventional 9-leg pallet in which the
legs may extend four inches from the floor to the deck, and the
deck may be two inches tall, in the platform 140 the channels 142
are about 1/2 inch deep, while the total deck 146 is about 1.5
inches tall. Thus it will be seen that the platform 140 has
protrusions which extend below the tine engagement surfaces 148 of
the deck 146 a distance which is less than the distance from the
tine engagement surfaces 148 to the top surface 150 of the deck.
The platform 140 also has the improved ground contacting surface
area as discussed above. The platform 140 may also be made as a
single sheet thermoformed part, similar to the part shown in FIG.
1, or as a molded foam part.
It should be noted that strap-receiving grooves may also be
provided on the twin sheet thermoformed and foam molded embodiments
to perform the functions discussed with respect to FIG. 5.
Moreover, the single sheet thermoformed and foam molded embodiments
may also be provided with a peripheral groove to receive a pallet
sleeve. Also, although only the foam molded embodiment has been
illustrated in use as a cap, the other embodiments discussed above
may also be used as a cap, and may have the interfitting dimples
and protrusions to restrict horizontal movement.
It is understood that the invention is not limited to the
particular construction and arrangement of parts herein illustrated
and described, but embraces such modified forms thereof as come
within the scope of the following claims.
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